Search

A hexacoordinated Co(II) complex of [CoL(NCS)2]·2DMSO (1) composition, where L is tetradentate bis-quinolyl hydrazone 2,2′-(2,2′-(butane-2,3-diylidene)bis(hydrazin-1-yl-2-ylidene))diquinoline, has been synthesised and characterized by IR, SCXRD, and AC and DC magnetic measurements. Due to helix-like distortion of the complex, the Co(II) coordination polyhedron is distorted towards trigonal prismatic symmetry. Complex 1 demonstrates slow relaxation of magnetization in an applied DC magnetic field of 1000 Oe, which is well described by the Raman mechanism. The performed CASSCF+NEVPT2 calculations provide clear insight into the origin of the magnetic anisotropy in 1. [ABSTRACT FROM AUTHOR]

In this work, a new binuclear nitrosyl complex with 3.4-dichlorothiophenolyl ligands [Fe2(SC6H3Cl2)2(NO)4] has been synthesized. Nitrosyl iron complexes (NICs) are systems for the storage and delivery of NO in the body. There is a dynamic equilibrium between dinitrosyl iron units bound to low molecular weight ligands and high molecular weight (protein) ligands in vivo. From this point of view, the transformation of the studied complex in DMSO and buffer, as well as in biological systems, has been analyzed. In DMSO, it decomposes into mononuclear NICs, which quickly decay in buffer solutions with NO release. The high molecular weight product is formed as a result of the binding of the complex to bovine serum albumin (the Stern–Volmer constant is 2.1 × 105 M−1). In this case, the complex becomes a prolonged NO-donor. Such a long-term effect has been observed for the first time. Similarly, in a system with oxyhemoglobin, NO generation is slower; the UV-vis spectra show a gradual formation of methemoglobin. On the other hand, reduced glutathione has little effect on the NO-donor properties of the complex despite the fact that ligand substitution is observed in the system and a binuclear product is formed. Mucin binds the complex, and the decomposition mechanism is different from that for buffer solutions. Thus, these proteins and glutathione are able to participate in the transformation of the complex and modulate its properties as a potential drug. [ABSTRACT FROM AUTHOR]

In this work a new donor of nitric oxide (NO) with antibacterial properties, namely nitrosyl iron complex of [Fe(C6H5C-SNH2)2(NO)2][Fe(C6H5C-SNH2)(S2O3)(NO)2] composition (complex I), has been synthesized and studied. Complex I was produced by the reduction of the aqueous solution of [Fe2(S2O3)2(NO)2]2− dianion by the thiosulfate, with the further treatment of the mixture by the acidified alcohol solution of thiobenzamide. Based on the structural study of I (X-ray analysis, quantum chemical calculations by NBO and QTAIM methods in the frame of DFT), the data were obtained on the presence of the NO...NO interactions, which stabilize the DNIC dimer in the solid phase. The conformation properties, electronic structure and free energies of complex I hydration were studied using B3LYP functional and the set of 6–31 + G(d,p) basis functions. The effect of an aquatic surrounding was taken into account in the frame of a polarized continuous model (PCM). The NO-donating activity of complex I was studied by the amperometry method using an "amiNO-700" sensor electrode of the "inNO Nitric Oxide Measuring System". The antibacterial activity of I was studied on gram-negative (Escherichia coli) and gram-positive (Micrococcus luteus) bacteria. Cytotoxicity was studied using Vero cells. Complex I was found to exhibit antibacterial activity comparable to that of antibiotics, and moderate toxicity to Vero cells. [ABSTRACT FROM AUTHOR]

Three novel bis- and trinitroso compounds derived from 1,3,5- trihydrohybenzene (phloroglucinol), 2,4,6–trihydroxy benzoic acid, and 2,4,6-trihydroxyacetophenone were isolated, their spectral characteristics, ionization constants and thermodynamic parameters of dissociation process were calculated. The comparison of the stability of nitroso and hydroxylimino tautomeric forms was performed by DFT calculations. Nine complexes of the ligands with Cu(II), Cd(II), and Fe(III), were isolated and studied by elemental analyses, X Ray analysis and spectroscopic methods. According to the crystal structure determination, the Cd complex with the phloroglucinol based ligand exists in the form of a binuclear compound. The QTAIM Bader topological analysis indicated that the binuclearity of the Cd complex is due to strong interatomic interactions between Cd atoms with bifurcate carbonyl groups of the ligands and strong H-interactions involving coordinated and lattice water molecules. The equilibria of reactions of complex formation of the organic species with Cu2+, Cd2+, and Fe3+ was studied by spectrophotometric titration, and the composition of the complexes in solutions and their stability constants were calculated. The ability of the isolated organics to remove metal cations from the aqueous solutions was studied in the pH interval 3–6 and the rate of Cu2+ removal from aqueous solutions was found close to 100%. [ABSTRACT FROM AUTHOR]

[Display omitted] A new complex of nickel acrylate and 4 ' -phenyl-2,2 ' :6 ' ,2 " - terpyridine, analogs of which have been previously used to obtain self-healing metallopolymers, has been prepared. The complex was analyzed by X-ray diffraction, IR and UV absorption spectroscopy, differential scanning calorimetry and thermogravimetric analysis. The values of effective activation energy of solid-phase polymerization and heat of double bond opening for this complex have been calculated. [ABSTRACT FROM AUTHOR]

In this work, a new binuclear nitrosyl complex with 3.4-dichlorothiophenolyl ligands [Fe 2 (SC 6 H 3 Cl 2 ) 2 (NO) 4 ] has been synthesized. Nitrosyl iron complexes (NICs) are systems for the storage and delivery of NO in the body. There is a dynamic equilibrium between dinitrosyl iron units bound to low molecular weight ligands and high molecular weight (protein) ligands in vivo . From this point of view, the transformation of the studied complex in DMSO and buffer, as well as in biological systems, has been analyzed. In DMSO, it decomposes into mononuclear NICs, which quickly decay in buffer solutions with NO release. The high molecular weight product is formed as a result of the binding of the complex to bovine serum albumin (the Stern-Volmer constant is 2.1 × 10 5 M -1 ). In this case, the complex becomes a prolonged NO-donor. Such a long-term effect has been observed for the first time. Similarly, in a system with oxyhemoglobin, NO generation is slower; the UV-vis spectra show a gradual formation of methemoglobin. On the other hand, reduced glutathione has little effect on the NO-donor properties of the complex despite the fact that ligand substitution is observed in the system and a binuclear product is formed. Mucin binds the complex, and the decomposition mechanism is different from that for buffer solutions. Thus, these proteins and glutathione are able to participate in the transformation of the complex and modulate its properties as a potential drug.

2-Benzo[ b ]thienyl fulgides and fulgimides containing bulky diphenylmethylene substituents were synthesized in the form of their ring-opened E - or Z- isomers. In contrast to the majority of known fulgides/fulgimides, that form colored ring-closed structures under UV irradiation, the obtained compounds undergo an irreversible transformation leading to decoloration of their solutions. This rearrangement with the formation of the dihydronaphthalene core appeared to be by 2-3 orders of magnitude more efficient than for the known diphenylmethylene(aryl(hetaryl))fulgides. The molecular structures of E - and Z- isomers and of products of the photoinduced rearrangement completed by 1,5-H shift reaction, 3a,4-dihydronaphtho[2,3- c ]furans(pyrroles) C , were established based on the data of 1 H and 13 C NMR spectroscopy and X-ray diffraction studies., (Copyright © 2020, Rybalkin et al.; licensee Beilstein-Institut.)